A mobile communication device and its serving base station wirelessly communicate to provide voice, Internet, email, text, video, and other communication services. As the mobile communication device moves about, the serving base station hands-off the mobile communication device to another target base station. After the hand-off, the target base station then becomes the serving base station, and subsequently, this new serving base station will hand-off the mobile communication device to another target base station.
In some communication systems, the mobile communication device receives a list of nearby base stations from the serving base station. If the mobile communication device detects an unacceptable loss of wireless signal strength for the serving base station, then the mobile communication device selects another base station from the list having the best wireless signal strength to be the target base station. The mobile communication device then initiates a hand-off from the serving base station to the selected target base station.
Serving base stations may also initiate hand-offs when they become overloaded and need to reduce the number of mobile communications devices they serve. Typically, the overloaded base station hands-off the mobile communication devices to more lightly loaded base stations. Serving base stations may also initiate hand-offs based on low wireless signal strength.
Overview
A mobile communication device wirelessly transfers user communications to a first wireless base station. The mobile communication device determines a first metric based on a load indicator for the first base station. The mobile communication device identifies a second wireless base station and determines a second metric based on a load indicator for the second base station. If the second metric is superior to the first metric, the mobile communication device determines if the second base station has sufficient performance characteristics for communication with the device. If the performance is sufficient, the mobile communication device initiates a hand-off from the first base station to the second base station. The mobile communication device may use additional factors to determine the first and second metrics.